1. Field of the Invention
This invention relates to the production of fully refined steel from high phosphorous iron ores. It is well known that phosphorous is a contaminant in steel making and has a deleterious effect on nearly every grade of steel. Conventional processes for steel making cannot use high phosphorous iron ores without substantially increasing the cost of manufacture.
In steel making processes wherein high phosphorus ores are charged to the blast furnace and the hot metal produced in the blast furnace is then sent on to a basic oxygen furnace, or open hearth furnace, or electric furnace for refining into finished steel, the phosphorous is not removed in the blast furnace and remains in the hot metal. Accordingly, it is necessary to use more complicated and expensive refining methods such as double slagging, that materially increases the cost of steel manufacture and reduces the capacity of the steel-making facility. This same problem of carry over of the phosphorous into the refining furnace exists when high phosphorous ores are used in direct reduction processes, wherein sponge iron is produced as an intermediate product and is then charged to a refining furnace such as an electric furnace or induction furnace or the like. Accordingly, none of the prior art processes in use today enable a steel maker to effectively remove phosphorous in the slag during the refining because the phosphorous is reduced and remains in the steel.